Method for manufacturing high density pile fabrics

ABSTRACT

The present invention relates to a method for face-to-face weaving of a pile fabric on a weaving machine, pile forming pile warp yarns ( 6, 7, 8, 9, 16, 17, 18, 19 ) being interlaced alternately around a weft yarn ( 1 ) in the upper fabric and around a weft yarn ( 1 ) in the lower fabric and non pile forming pile warp yarns ( 6, 7, 8, 9, 16, 17, 18, 19 ) being interlaced in one of the backing fabrics in accordance with a predetermined pattern, the said weaving machine comprising at least three weft insertion means and that at each weft insertion cycle only one weft yarn is inserted, the non pile forming pile warp yarns ( 6, 7, 8, 9, 16, 17, 18, 19 ) to be interlaced are positioned on a different level (N 1 , N 2 ) and, in successive series of four weft insertion cycles (a, b, c, d) each time during two successive weft insertion cycles one weft yarn ( 1 ) being inserted (a, b) under the two levels (N 1 , N 2 ) and one weft yarn ( 1 ) being inserted above the two levels (N 1 , N 2 ) and each time, during two other successive weft insertion cycles (c, d) one weft yarn ( 1 ) being inserted in each of these weft insertion cycles between the said levels (N 1 , N 2 ).

The present invention relates to a method for manufacturing face-to-facewoven pile fabrics, two backing fabrics being woven above one another ona weaving machine by inserting weft yarns in successive weft insertioncycles between binding and tension warp yarns, the pile warp yarnsforming a pile in at least one part of the pile fabric by beingalternately interlaced around a weft yarn in the upper backing fabricand around a weft yarn in the lower backing fabric and pile warp yarnsforming no pile in at least another part of the pile fabric and beinginterlaced in one of the backing fabrics in accordance with apredetermined pattern. More particularly, the present invention isrelating to a high density pile fabric manufactured in accordance withthe present method.

Furthermore, the present invention relates to a weaving machine providedfor the method according to the invention to be carried out.

Hand-knotted fabrics are characterized by:

-   -   a high density;    -   a delicate design in many colours (six colours and more);    -   a nice back.

When weaving there is an evolution to systematically increase thedensity of pile fabrics. Where in weaving, the weaving reed used to be arestriction for densities above 550 pile warp yarns per metre, becausethe number of reed dents per metre was restricted to 550, the Europeanpatent publication EP 1 347 086 proposes a method for the densities of apile fabric to be increased by providing two pile warp systems per reeddent in combination with a suitable arrangement of the backing warpyarns in this reed dent in order to realize a certain separation betweenthe pile warp yarns of the two pile warp systems within the same reeddent.

In this manner, it will be possible to produce fabrics having 700 andeven 800 pile warp systems per metre in the weft direction. It ispossible to apply this method with 1/1 V-weave as represented in EP 1347 086 on a double rapier weaving machine, the pattern forming pilewarp yarn being interlaced alternately in each fabric around a weft atthe back of the fabric and then around a weft on the pile face of thefabric.

With this method therefore, only half the pile will be interlaced arounda weft at the back of the fabric, so that the other half of the pilewill be interlaced less securely on the pile face of the said fabric,which may be deduced immediately from the pattern which will be observedat the back of the fabric. This pattern will contain only half of thepile points and therefore is less delicate than the pattern at the frontof the fabric.

In a 1/2 V-weave all pile warp yarns are indeed interlaced around a weftat the back of the fabric. Here, the pile warp yarns being interlacedsecurely, which is clearly shown by the pattern at the back of thecarpet. The pattern at the back clearly corresponds to the pattern atthe front, because of which, a quality may be approached which will bebetter in accordance with a hand-knotted carpet than the one of a 1/1V-weave which is not fully interlaced through to the back of the fabric.

Only, when weaving the 1/2 V texture by means of the multiple rapiertechnique, the problem may occur that mixed contours are produced,preventing delicate designs from being formed, which is ratherinconvenient in fabrics of this density.

Mixed contour mean that two pile tufts of a different pile warp yarn(colour) will occur between two successive wefts in a face-to-facefabric, which will be crossing and standing upright next to one anotherin a face-to-face fabric. Because the two pile tufts are crossing withthis colour change, they will take up a wrong position with respect toone another in accordance with what is desired and this will cause thepattern of the fabric to become indistinct.

It is known that certain mixed contours may occur in one of the fabricsor in both fabrics at certain colour (pile warp yarn) changes, dependenton the positions taken up by the yarns of these changing pile warp yarnswhen they are not forming the pattern and are interlaced as dead pile.Thus:

-   -   when the pile change occurs from a pile warp yarn being        interlaced as a dead pile in the upper fabric, to a pile warp        yarn being interlaced in the lower fabric, a mixed contour will        never be produced;    -   when the pile change occurs from a pile warp yarn being        interlaced as a dead pile in the upper fabric, to a pile warp        yarn being interlaced in the upper fabric, a mixed contour will        be produced in the upper fabric;    -   when the pile change occurs from a pile warp yarn being        interlaced as a dead pile in the lower fabric, to a pile warp        yarn being interlaced in the lower fabric, a mixed contour will        be produced in the lower fabric;    -   when the pile change occurs from a pile warp yarn being        interlaced as a dead pile in the lower fabric, to a pile warp        yarn being interlaced in the upper fabric, a mixed contour will        be produced in both fabrics;

Such mixed contour effects may be avoided by providing two lines of thesame colour (the same pile warp yarn) in the card design after oneanother and to apply to them the method described in the European patentpublication EP 9 27782 and, of at least one of the pile warp yarnsinvolved in the pile change, one lift plan before the pile change or onelift plan after the pile change being replaced by a correction liftplan.

In practice, such correction lift plans may be applied automatically tothe processing software transforming the design into a file in order toactivate the Jacquard machine. However, in order to be able to applythis method, a number of rules have to be respected as indicated whensetting up the design, namely that the correction lift plan may only beapplied to produce the effect expected, when during two successive pileplans the pile is formed by one and the same pile warp yarn.

In the very delicate patterns to be woven by means of the devices asdescribed above, applying these applications to the design is verylabour intensive. Moreover, the liberty of designing in delicatedrawings will be restricted.

Moreover, the fact of mixed contours occurring or not, depends on theposition of the pile warp yarns in the weaving creel, for the positionof the pile warp yarns will determine in which fabric the pile will beinterlaced.

Although, from a technical point of view, it is possible to avoid mixedcontours, we find that in practice, quite some fabrics are still showingmixed contours. Moreover the delicate designing requires (typical offabrics imitating hand-knotted carpets) a freedom of designing, which isnot always to be realized by avoiding mixed contours as described above.Double colour rows in order to avoid mixed contours are sometimesinconvenient to the delicacy of a design.

The 1/1V method and the 1/2V method as described before, moreover, havethe disadvantage that they are restricted to about 40 pile warp yarnsper centimetre with double rapier weaving machines which are normallyused.

At higher densities of pile warp yarns, there will be problems as to theperfectness of the quality of the back and the dead pile protruding fromthe back of the fabric. This certainly is the case with acrylic andwoolen yarns having a surface which is more coarse. With polypropyleneyarns also, which are smoother, these problems will occur, but in thatcase rather from 42 to 45 pile warp yarns per centimetre.

This means, that a fabric having a high density and many colours willcause problems to be woven, both with a 1/1V and 1/2V weave, on a doublerapier weaving machine in the following structures:

-   -   600 pile warp systems per metre in 7 chore and more:    -   700 pile warp systems per metre in 6 chore and more:    -   800 pile warp systems per metre in 5 chore and more.

The purpose of this invention consists in providing a method to weave ahigh density pile fabric, without mixed contours, without the need ofthe design to be adapted and, moreover, a nice back being realized.

The purpose of the invention is attained by providing a method for theface-to-face weaving of a pile fabric, two backing fabrics, one abovethe other, being woven on a weaving machine, by inserting weft yarns insuccessive weft insertions cycles between binding and tension warpyarns, pile warp yarns forming the pile in at least one part of the pilefabric by interlacing alternately around a weft yarn in the upperbacking fabric and around a weft yarn in the lower backing fabric andpile warp yarns not forming a pile in at least one other part of thepile fabric and being interlaced in one of the backing fabrics inaccordance with a predetermined pattern, the said weaving machinescomprising at least three weft insertion means and only one weft yarnbeing inserted in each weft insertion cycle, the non pile forming pilewarp yarns being positioned to be interlaced in the upper fabric, andthe non pile forming pile warp yarns to be interlaced in the lowerfabric being positioned each on a different level and, in successiveseries of four weft insertion cycles, each time during two successiveweft insertion cycles, one weft yarn being inserted below the two levelsand one weft yarn being inserted above both levels and each time duringtwo other successive weft insertion cycles, one weft yarn being insertedbetween the said levels in each of these weft insertion cycles.

The expert skilled in the art knows that mixed contours may be avoidedwhen weaving pile fabrics by inserting only one weft into the fabric ateach weft insertion cycle. This method is known for use on aface-to-face weaving machine having only one weft insertion means(single gripper weaving machine).

As these devices for face-to-face weaving of pile fabrics are no longermanufactured, these methods are applied to double gripper weavingmachines, where either at each weft insertion cycle, either one of theweft insertion means is disengaged or no weft yarn will be presented toone of the weft insertion means.

Applying these methods to pile fabrics with densities the number of pilewarp yarns per centimetre exceeding 40, has the disadvantage that theweaving process will cause great difficulties accompanied by a largenumber of disturbances. Moreover, the quality of the fabric producedwill be inferior, the back of the fabric is not a nice one, because(dead) non pile forming pile warp yarns will be visibly protruding incertain places from the back of the fabric. As the density of the fabricin the weft direction will be increasing and the number of colours (pilewarp yarns) being used is likewise increasing, this problem will becomeonly bigger.

After thorough research into the causes of this problem it has beenfound that, when manufacturing such fabrics, an enormous package of pilewarp yarns is found which are extending in the weft directionpractically next to one another (=number of pile warp yarnsystems×number of chores). A Jacquard machine will position these pilewarp yarns at each weft insertion cycle with respect to the weftinsertion means. At such densities of pile warp yarns, changing theposition of these mass of pile warp yarns with respect to the weftinsertion means is a complicated operation with a Jacquard machine. Onthe one hand, there is the heavy load on the Jacquard machine necessaryto move this mass of non pile forming pile warp yarns. On the other handthese non pile forming pile warp yarns will be moving only relativelyslightly with respect to one another, but yet this relatively slightmotion of the non pile forming yarns with respect to one another meansthat uncontrollable forces and tensions will occur, among others becauseof the yarns becoming entangled and the consumption of the separate pilewarp yarns being increased. Thus, it will be impossible to predictexactly which yarn will be moving, when and along which distance.Because of this, these non pile forming pile warp yarns will beirregularly interlaced during the formation of the fabric, so that thefabric will show an imperfect aspect (this will be noted essentially atthe back of the fabric).

The solution to this problem consist in choosing the manufacture of suchhigh density fabrics on a face-to-face-weaving machine with three weftinsertion means, only one of the three weft insertion means inserting aweft at each weft insertion cycle, whereas either the other weftinsertion means do not extend through the shed or do not take along anyweft yarns when moving through the shed. With this method it is possibleto insert the wefts in both fabrics, above between or below the levelsof the non pattern forming pile warp yarns, the non pattern forming pilewarp yarns being interlaced in the upper fabric situated on a firstlevel and the non pattern forming pile warp yarns in the lower fabric ona second level.

By this method it is possible to manufacture high density pile fabricswithout mixed contours occurring.

In a particular method according to the invention, pile forming pilewarp yarns are interlaced only around weft yarns having been insertedbelow or above the two levels at which non pile forming pile warp yarnsare positioned to be interlaced in their backing fabrics.

In a preferred method according to the invention, the non pile formingpile warp yarns to be interlaced in the upper fabric and the non pileforming pile warp yarns to be interlaced in the lower fabric willmaintain their positions with respect to the weft insertion means duringthe non pile formation. This has the great advantage that the non pileforming pile warp yarns which are interlaced in the upper fabric, willmaintain their positions between the upper and the central weftinsertion means and that the non pile forming pile warp yarns which areinterlaced in the lower fabric will maintain their positions between thecentral and the lower weft insertion means. In this manner, only thepile forming pile warp yarns will have to be moved out of or through thebundle of pile warp yarns. This manner very strongly favours the formingof the shed at higher densities of pile warp yarns and will finally leadto a lower consumption of pile warp yarns.

In a more particular method according to the invention the pile warpyarns are inserted in series of four successive weft insertion cycles,each time one weft yarn, around which a pile forming warp yarn isinterlaced, being inserted in the first two weft insertion cycles ineach of the fabrics, with for the upper fabric the upper weft insertionmeans and for the lower fabric the lower weft insertion means and thatin the third and fourth weft insertion cycles of the said series, intoeach of the fabrics, each time one weft yarn is inserted between thesaid levels by means of the central weft insertion means.

In a preferred embodiment of the method according to the invention,during the successive weft insertion cycles of the said series, one weftyarn is inserted alternately in order to form the upper fabric and oneweft yarn in order to form the lower fabric or vice versa.

In a more preferred method according to the invention, one weft yarn isinserted in the first weft insertion cycle by means of the lower weftinsertion means under the said levels, in the second weft insertioncycle, one weft yarn is inserted by mean of the upper weft insertionmeans above the said levels, in the third and fourth weft insertioncycles, successively one weft yarn is inserted each time by means of thecentral weft insertion means, on the pile face of the upper and lowerfabric respectively.

In another embodiment of the method according to the invention, in thefirst weft insertion cycle, one weft yarn is inserted under the saidlevels by means of the lower weft insertion means, in the second weftinsertion cycle, one weft yarn is inserted above the said levels bymeans of the upper weft insertion means and in the third and fourth weftinsertion cycles, each time one weft yarn is inserted successively bymeans of the central weft insertion means on the pile face of the lowerand upper fabric respectively.

In a more preferred method according to the invention, one weft yarn isinserted in the first weft insertion cycle by means of the upper weftinsertion means above the said levels, in the second weft insertioncycle, one weft yarn is inserted by means of the lower weft insertionmeans under the said levels and in the third and fourth weft insertioncycles, one weft yarn is inserted successively each time by means of thecentral weft insertion means, on the pile face of the upper and lowerfabric respectively.

In a preferred embodiment of the method according to the invention, oneweft yarn is inserted in the first weft insertion cycle by means of theupper weft insertion means above the said levels, in the second weftinsertion cycle one weft yarn is inserted by means of the lower weftinsertion means under the said levels and in the third and fourth weftinsertion cycles, one weft yarn is inserted successively each time bymeans of the central weft insertion means, on the pile face of the lowerand upper fabric respectively.

In a more particular embodiment of the method according to theinvention, a first and a second pile warp yarn are performing a pilechange, the second pile warp yarn becoming pile forming by, after thefourth weft insertion cycle of a series, being interlaced in a pileforming manner around a weft yarn inserted during the first weftinsertion cycle of a next series at the back of the backing fabric andthe first pile warp yarn stopping to form the pile by interlacing thesaid first pile warp yarn after the second weft insertion cycle of theseries, in its backing fabric without forming a pile. This means that inboth fabrics the pile tufts of adjacent pile burls are separated, eachtime, by an intermediate weft, because of which there is no possibilityfor the adjacent pile burls to cross one another and no mixed contourswill occur. A fine delicate design is obtained on the pile face of thefabric, whereas all pattern forming pile is interlaced at the back ofthe fabric, so that a nice pattern is formed also at the back of thefabric.

In a further preferred embodiment of the method according to theinvention, during at least one series of four successive weft insertioncycles, pile forming pile warp yarns are interlaced around each weftyarn inserted during the series.

If a same pile warp yarn is interlaced around the four successive weftsof a series, pile tufts of different adjacent pile burls will indeed befound without being separated by a weft yarn, but this wefts are notcrossing in the face-to-face fabric, so that there will be no mixedcontour. The two pile tufts of the same colour are standing nicelyupright next to one another and they will also maintain this position inthe fabric. This means that the pile density of the fabric in part ofthe fabric or almost the entire fabric may be increased without mixedcontours occurring and with preservation of a delicate design and a niceback of the fabric.

In a more particular method according to the invention, the tension warpyarns of the upper and lower fabric are positioned outside the upper andlower weft insertion means respectively, each time no weft yarn isinserted at the back of the respective fabric and the tension warp yarnsof the upper and lower fabric are positioned between the upper and thelower weft insertion means respectively and the central weft insertionmeans being positioned, each time a weft yarn is inserted at the back ofthe respective fabric. This has, among others, the advantage that thetension warp yarn in the lower fabric is used as a support for the lowerweft insertion means when it is moving through the shed without a weftyarn.

High densities of warp yarns in the weft direction are realized by acombination of a large number of warp yarn systems per metre and a largenumber of chores. The large number of warp systems per metre isobtained, by providing at least two pile warp systems per reed dent, ina particularly advantageous embodiment of the method according to theinvention. This has the great advantage that by using this method,fabrics having a high density, more particularly of more than 40 pilewarp yarns per centimetre, may be manufactured, without mixed contoursoccurring.

In a preferred embodiment of the method according to the invention, thesaid weaving machine is provided, either for disengaging at least oneweft insertion means or/and for not presenting a weft yarn to at leastone weft insertion means.

In a more preferred embodiment of the method according to the invention,the weft insertion means are provided with a driving device in order tocarry the weft insertion means through the shed and the weaving machineis provided for selecting any weft insertion means, during each cycle,whether a weft insertion means will be carried through the fabric or notby connecting or disconnecting the respective weft insertion means to orfrom its driving device.

More particularly connecting or disconnecting the weft insertion meansto or from its driving device may occur in an electromotive,electropneumatic or electrohydraulic manner.

Another subject of the present patent application relates to a pilefabric, the said fabric comprising at least one area manufacturedaccording to a method in correspondence with one of the claims 1 up toand including 16.

Furthermore, the present invention relates to a weaving machine forweaving a face-to-face fabric comprising binding and tension warp yarns,weft yarns and at least 40 pile warp yarns per centimetre which, in atleast one part of the fabric, are interlaced alternately in the upperand lower backing fabric, forming a pile around a weft yarn and which,at least in one other part of the fabric are interlaced, not forming apile, in one of the backing fabrics, the said weaving machine comprisingthree weft insertion means and being provided for inserting only oneweft yarn at each weft insertion cycle, the pile warp yarns not formingthe pile before being interlaced in the upper fabric and the pile warpyarns not forming the pile before being interlaced in the lower fabric,each being positioned on a different level and where in successiveseries of four weft insertion cycles, each time, one weft yarn isinserted under both levels during two successive weft insertion cyclesand one weft yarn being inserted above both levels and each time, duringtwo other successive weft insertion cycles, in each of these weftinsertion cycles, one weft yarn is inserted between the said levels.

In a preferred embodiment of the weaving machine according to theinvention, the said weaving machine is provided for carrying out themethod according to one of the claims 2 up to and including 16.

In a particularly preferred embodiment of the weaving machine accordingto the invention, the said weaving machine is a face-to-face threerapier weaving machine provided with a non-open shed Jacquard machine.

In another particularly preferred embodiment of the weaving machineaccording to the invention, the said weaving machine is a face-to-facethree rapier weaving machine provided with an open shed Jacquardmachine.

In the following detailed description of the method according to thepresent invention the said particulars and advantages of the inventionare further explained. It may be obvious that the only intention of thisdescription exists in clarifying the general principles of the presentinvention by a concrete example, and that nothing of this descriptionmay be interpreted as being a restriction of the scope of the patentrights demanded for in the claims nor of the field of application of thepresent invention.

In the following description, by means of reference numbers, referenceis made to the attached figures of which:

FIG. 1 is representing a method according to the invention in accordancewith a 1/2V-weave;

FIG. 2 is representing a method according to the invention in accordancewith a 1/2V-weave, in which locally also a 2/2V-weave is realized;

FIG. 3 is representing a method according to the invention in accordancewith a 1/2V-weave, in which locally also a 1/1V-weave is realized;

The face-to-face pile fabric represented in the figures consists of anupper an a lower backing fabric. Both backing fabrics consist of bindingwarp yarns, tension warp yarns and weft yarns. Pile forming pile warpyarns are alternately interlaced in the upper and the lower fabricaround a weft yarn, whereas non pile forming (dead) pile warp yarns areinterlaced in the upper or the lower backing fabric and each of which ispositioned on a different level (N1, N2).

Each figure is made up of four parts (a), (b), (c) and (d), where (a) isrepresenting the course of the pile warp yarns (6, 7, 8, 9) of one pilewarp system within one reed dent with the accessory part of the backingwarp yarns (4, 5) and (b), the pile warp yarns (16, 17, 18, 19) ofanother pile warp system within the same reed dent with its accessorybacking warp yarns (14, 15). Both in (a) and in (b) the positions of theweft insertion means are indicated with respect to the warp yarns and isindicated with which weft insertion means a weft yarn (1) is indeedinserted (little balls in black colour). The little balls (2) in whitecolour are representing the level of the weft insertion, where the weftinsertion means is not carried through the shed. The little cross-markedballs (3) are representing a weft insertion means level where the weftinsertion means is carried through the shed without carrying a weft yarn(1). Indication of the little white balls (2) and the littlecross-marked balls (3) within the figures is only by way of example of acombination of the various possibilities to carry no weft yarn (1)through the shed. Any random combination of succession or variation ofone of these or other possibilities to carry no weft yarn (1) throughthe shed likewise falls within the scope of the present invention.

The figures (c) and (d) are representing the actual texture of thefabric which is realized with the weft yarns (1) which are actuallyinserted with the pile warp system represented in (a) and (b)respectively.

In correspondence with the method according to the invention, twobacking fabrics are woven one above the other on a weaving machinecomprising at least three weft insertion means and only one weft yarn(1) being inserted at each weft insertion cycle (a, b, c, d), the nonpile forming pile warp yarns to be interlaced in the upper fabric andthe non pile forming pile warp yarns to be interlaced in the lowerfabric each being positioned on a different level (N1, N2) and insuccessive series of four weft insertion cycles (a, b, c, d,) each timeduring two successive weft insertion cycles (a, b) one weft yarn (1)being inserted under the two levels (N1, N2) and one weft yarn (1) beinginserted above the two levels (N1, N2) and each time during two othersuccessive weft insertion cycles (c, d) one weft yarn (1) being insertedin each of these weft insertion cycles between the said levels (N1, N2).

By using a three rapier machine, it will be possible for the pile warpyarns which are not pile forming and which are interlaced at level (N1)in the upper fabric two maintain their positions between the upper andthe central weft insertion means. The non pile forming warp yarns whichare interlaced in the lower fabric on level N2, will maintain theirpositions between the central and the lower weft insertion means,Therefore, instead of moving the dead pile with respect to one of theweft insertion means, inserting successive wefts into a backing fabric(as is the case when weaving on a face-to-face single or double gripperweaving machine), each time the weft insertion means may be selectedwhich, with respect to the stationary non pile forming pile, will insertthe right weft yarn in order to obtain the weave structure desired. Inthis manner, only the pile warp yarns forming the pile have to be movedout of or through the bundle of pile warp yarns.

This method will strongly favour the forming of the shed for weavingpile fabrics having a high density of pile warp yarns and willultimately lead to a lower consumption of pile warp yarns. With coarsepile warp yarns, such as for instance woolen and acrylic yarns, thisfavourable effect is important in order to weave fabrics having morethan 40 pile warp yarns per centimetre in the weft direction. But alsowith the smoother yarns of polypropylene such a method is offering areal advantage with respect to the fabric being neat and clean atdensities as from 45 pile warp yarns per centimetre in the weftdirection.

The method has the advantage that the course of the yarn will becomesmoother and the consumption of pile warp yarn will be reduced, so thatit will be possible to insert more wefts and more pile rows percentimetre in the warp direction and will lead to achieve a much cleanerpattern on the back of the carpet, because the dead pile have a stilllower tendency to protrude from the backing fabric.

In FIG. 1, a method and a fabric according to the invention arerepresented, a weft yarn (1) actually being carried through the shed insuccessive series of four weft insertion cycles (a, b, c, d), in thefirst cycle (a) only by means of the lower weft insertion means, in thesecond cycle (b) a weft yarn (1) being actually carried through the shedonly by means of the upper weft insertion means, and in the third (c)and fourth (d) cycles each time a weft yarn (1) is actually carriedthrough the shed only by means of the central weft insertion means.

The pile forming pile warp yarn (6, 7, 8, 9, 16, 17, 18, 19) isinterlaced alternately around the weft (1) inserted under the two levels(N1, N2) at the back of the lower fabric, in the first cycle (a) andaround the weft (1) inserted above the two levels (N1, N2) at the backof the upper fabric in the second cycle (b). The said pile forming pilewarp yarn remains in the third (c) and fourth (d) cycles respectivelyunder and above the wefts (1), which are inserted by means of thecentral weft insertion means between the two levels (N1, N2). In thismanner the pile is formed in a 1/2V-weave. A pile forming pile warp yarn(6, 7, 8, 9, 16, 17, 18, 19) which is stopping its pile formation andwill be interlaced in the upper fabric as a dead pile will, is moving,after being interlaced in the second weft insertion cycle (b) of aseries around the weft (1) in the upper fabric above the central rapier,and will further remain in a position (N1) between the central and theupper weft insertion means until the yarn will become pile formingagain.

A pile forming pile warp yarn (6, 7, 8, 9, 16, 17, 18, 19), which isstopping its pile formation and will be interlaced in the lower fabricas a dead pile will, is moving after being interlaced in the second weftinsertion cycle (b) of a series around the weft (1) in the upper fabricunder the central rapier and will further remain in a position (N2)between the central and the lower weft insertion means until the yarnwill become pile forming again.

It may be noticed that the wording that the pile warp yarn which isstopping to form a pile is taking up a position above or under thecentral weft insertion means, in this third (c) weft insertion cycle,means that as no weft is inserted by the outermost weft insertion means,this pile warp yarn may take up a position also above the upper or underthe lower weft insertion means respectively, instead of taking up aposition between the central and the outermost weft insertion means. Theresult in the fabric will be the same as pattern forming on the pileface and at the back is concerned.

A pile forming pile warp yarn (6, 7, 8, 9, 16, 17, 18, 19) which isinterlaced as a dead pile in the upper or lower fabric respectively ismoving, when it becomes pile forming, after the fourth weft insertioncycle (d) of a series, from its position above or under the centralrapier respectively, to a position under the weft (1) inserted by thelower gripper in a first weft insertion cycle (a) of a new series.

In this manner a fabric is obtained, each pile tuft being separated froman adjacent pile tuft by the presence of a weft yarn (1) and nocrossings of pile warp yarns situated next to one another will occur.This means that there will be no mixed contours and a clear pattern willbe formed on the pile face. The non pile forming (dead) pile warp yarns(6, 7, 8, 9, 16, 17, 18, 19) interlaced in the upper fabric willmaintain their positions (N1) between the central and the upper weftinsertion means without moving. The non pile forming (dead) pile warpyarns (6, 7, 8, 9, 16, 17, 18, 19) interlaced in the lower fabric willmaintain their positions (N2) between the central and the lower weftinsertion means without moving. Due to this the mass of non pile formingpile warp yarns will remain well in position (N1, N2) and welltensioned, so that a clean back with a clear formation of the pattern isrealized. Furthermore, due to this, the consumption of pile warp yarnsas dead piles will be restricted, which in turn will enable more weftsand pile rows per centimetre to be inserted into the fabric.

In order to realize even higher densities it is possible, in areas whereno pile changes will occur between pile forming pile warp yarns, tochoose in order, as represented in the FIGS. 2 b and 2 d, to positionthe pile forming pile warp yarns in the fourth weft insertion cycle (d)of a series, under the weft yarn inserted by the central gripper, sothat a local 2/2-V texture is formed in the lower fabric by which ahigher density is realized locally.

It is likewise possible (not represented in the figure) to position thepile forming pile warp yarns in the third cycle (c) above the centralweft insertion means, so that both in the lower and in the upper fabricthis higher density may be realized. Such local increases of density ofthe weave structure may be determined, for example, when setting up theoperating programme of the Jacquard machine on the basis of the fabricdesign in order to maintain a constant density of the fabric in theentire fabric.

In the FIGS. 3 a, b, c, d a weave structure is represented in which, onthe one hand, the actual weft insertion order is different from thetexture represented in FIG. 1, because the first weft (a) of a series offour wefts (a, b, c, d) is now a weft yarn which is inserted into theupper fabric with respect to the tension warp yarn at the back and thatthe second weft (b) of a series of four wefts is a weft yarn which isinserted into the lower fabric, at the back with respect to the tensionwarp yarn.

Furthermore, in FIG. 3, between their start as a pile forming pile warpyarn in a first cycle (a) of a series of four weft insertion cycles (a,b, c, d) and their stopping as a pile forming pile warp yarn in a secondcycle (b) of a further series of weft insertion cycles (a, b, c, d) pilewarp yarns (6) are also interlaced around one or several wefts insertedduring the last two weft insertion cycles (c, d) of one or severalseries (a, b, c, d), so that the pile density may be locally increased.The pile tufts of different colours thus becoming positioned next to oneanother and will not be separated by a weft yarn are not crossing in theface-to-face fabric so that no mixed contour will occur.

When in two adjacent pile warp systems within one reed dent some coloursof pile warp yarns will be made different, then when selecting one ofthese colours in view to form the pile, only half the density in theweft direction will be realized with respect to the pile formation ofpile warp yarns which are actually indeed present in each of the pilewarp systems. It is possible to almost compensate for this halving ofthe pile density by, for instance, also by interlacing in the weftdirection around the wefts situated on the pile face of the tension warpyarn. In this manner, it will be possible to increase the number ofchores in the fabric, practically maintaining the pile density and itstill being possible to avoid mixed contours.

According to the present invention, the weaving machine is equipped sothat all the weft insertion means in order to apply the method accordingto the invention are able to select, in every cycle (a, b, c, d),whether a weft insertion means will be carried through the shed or not.This is possible by connecting or disconnecting the weft insertion meansto or from its driving device in an electromotive, electropneumatic orelectrohydraulic manner in order to carry it through the shed. In thiscase, departing from the weaving pattern and the weave structure, itwill be possible to set up a programme, enabling the controller of theJacquard machine to activate any connecting device of a drive with itsweft insertion device in any machine cycle (a, b, c, d) in order torealize the fabric desired.

Fabrics according to the invention, such as represented in FIG. 1, forinstance, may be woven by means of a face-to-face three rapier weavingmachine provided with a Jacquard machine, functioning in accordance withthe non open shed principle, as described in the European patentpublication EP 627511, as this Jacquard machine will enable the pilewarp yarn either to be maintained in a position (N1) between the upperand the central rapier or in a position (N2) between the lower and thecentral rapier, as well as to form the pile from these positions. Itwill be obvious that the method according to the invention is likewiseapplicable using a face-to-face three rapier weaving machine providedwith an open shed Jacquard machine.

It is known that fabrics according to a 2/2V-weave, in which each piletuft in a fabric is surrounding two wefts, will enable the density ofthe fabric to be increased. In the method of the invention, this is notgenerally applicable, because this would mean that when passing from apile forming pile warp yarn to a second pile forming pile warp yarn, twopile tufts will become positioned next to one another which are notseparated from one another by a weft and are crossing, causing mixedcontours to occur, which is just what we want to avoid by the methodaccording to the invention.

A method which indeed may be actually applied in order to increase thedensity of the fabric without causing mixed contours, consists ininterlacing the pile warp yarn indeed around two wefts in places whereno colour change in the weft direction occurs and not to do this wherethere is a colour change.

The processing software for transforming the pattern of a fabric into aprogramme to activate a Jacquard machine, will be able to distributesuch transitions uniformly all over the fabric in order to obtain auniformly woven fabric. By a uniform distribution is meant that during anumber of machine cycles practically the same number of pile tufts isinterlaced around two wefts in each pile warp system.

1. Method for manufacturing face-to-face woven pile fabrics, two backingfabrics being woven above one another on a weaving machine by insertingweft yarns in successive weft insertion cycles (a, b, c, d) betweenbinding and tension warp yarns (4, 5, 14, 15), the pile warp yarnsforming a pile in at least part of the pile fabric by being interlacedalternately around a weft yarn (1) in the upper fabric and around a weftyarn (1) in the lower fabric and the pile warp yarns forming no pile inat least another part of the pile fabric and being interlaced in one ofthe backing fabrics in accordance with a predetermined pattern,characterized in that the said weaving machine comprises at least threeweft insertion means and in that only one weft yarn (1) is inserted ateach weft insertion cycle, the non pile forming pile warp yarn to beinterlaced in the upper fabric and the non pile forming pile warp yarnsto be interlaced in the lower fabric are each positioned on a differentlevel (N1, N2) and in successive series of four weft insertion cycles(a, b, c, d), each time during two successive weft insertion cycles (a,b), one weft yarn (1) being inserted under the two levels (N1, N2) andone weft yarn (1) being inserted above the two levels (N1, N2) and eachtime during two other successive weft insertion cycles (c, d), one weftyarn (1), in each of these weft insertion cycles being inserted betweenthe said levels (N1, N2).
 2. Method according to claim 1, characterizedin that pile forming pile warp yarns are interlaced only around weftyarns having been inserted below or above the two levels (N1, N2) atwhich non pile forming pile warp yarns are positioned to be interlacedin their backing fabrics.
 3. Method according to claim 1, characterizedin that the non pile forming pile warp yarns to be interlaced in theupper fabric, and the non pile forming pile warp yarns to be interlacedin the lower fabric, during the non pile formation, will maintain theirpositions with respect to the weft insertion means.
 4. Method accordingto claim 1, characterized in that the weft yarns (1) are inserted inseries of four successive weft insertion cycles (a, b, c, d), in thefirst two weft insertion cycles (a, b) in each of the fabrics, one weftyarn (1) being inserted around which a pile forming pile warp yarn isinterlaced by means of the upper weft insertion means for the upperfabric and by means of the lower weft insertion means for the lowerfabric and in that in the third and fourth weft insertion cycles (c, d)of the said series, each time, one weft yarn (1) being inserted betweenthe said levels (N1, N2) by means of the central weft insertion means.5. Method according to claim 1, characterized in that during thesuccessive weft insertion cycles (a, b, c, d) of the said series, oneweft yarn (1) is inserted alternately in order to form the upper fabricand one weft yarn (1) to form the lower fabric or vice versa.
 6. Methodaccording to claim 1, characterized in that one weft yarn (1) isinserted in the first weft insertion cycle (a) by means of the lowerweft insertion means under the said levels (N1, N2), one weft yarn (1)is inserted in the second weft insertion cycle (b) by means of the upperweft insertion means above the said levels (N1, N2), in the third (c)and fourth (d) weft insertion cycles each time, one weft yarn (1) isinserted successively by means of the central weft insertion means onthe pile face of the upper and lower fabric respectively.
 7. Methodaccording to claim 1, characterized in that one weft yarn (1) isinserted in the first weft insertion cycle (a) by means of the lowerweft insertion means under the said levels (N1, N2), one weft yarn (1)is inserted in the second weft insertion cycle (b) by means of the upperweft insertion means above the said levels (N1, N2), each time one weftyarn (1) is inserted successively in the third (c) and fourth (d) weftinsertion cycles by means of the central weft insertion means on thepile face of the lower and upper fabric respectively.
 8. Methodaccording to claim 1, characterized in that one weft yarn (1) isinserted in the first weft insertion cycle (a) by means of the upperweft insertion means above the said levels (N1, N2), one weft yarn (1)is inserted in the second weft insertion cycle (b) by means of the lowerweft insertion means under the said levels (N1, N2), each time, one weftyarn (1) is inserted successively in the third (c) and fourth (d) weftinsertion cycles by means of the central weft insertion means on thepile face of the upper and lower fabric respectively.
 9. Methodaccording to claim 1, characterized in that one weft yarn (1) isinserted in the first weft insertion cycle (a) by means of the upperweft insertion means above the said levels (N1, N2), one weft yarn (1)is inserted in the second weft insertion cycle (b) by means of the lowerweft insertion means under the said levels (N1, N2), each time, one weftyarn (1) is inserted successively in the third (c) and fourth (d) weftinsertion cycles by means of the central weft insertion means on thepile face of the lower and upper fabric respectively.
 10. Methodaccording to claim 1, characterized in that a first and a second pilewarp yarn will perform a pile change, the second pile warp yarn,becoming pile forming by being interlaced after the fourth weftinsertion cycle (d) of a series (a, b, c, d) around a weft yarn (1)inserted during the first weft insertion cycle of a next series of weftyarns (1) inserted at the back of the backing fabric, and the first pilewarp yarn stopping its formation of the pile by interlacing the saidfirst pile warp yarn in its backing fabric not forming a pile, after thesecond weft insertion cycle (b) of the series (a, b, c, d).
 11. Methodaccording to claim 1, characterized in that during at least one seriesof four successive weft insertion cycles (a, b, c, d) the pile formingpile warp yarns are interlaced around each weft yarn (1) inserted duringthe series.
 12. Method according to claim 1, characterized in that thetension warp yarns of the upper and the lower fabric are positionedoutside the upper and lower weft insertion means respectively, each timeno weft yarn (1) is inserted at the back of the respective fabric and inthat the tension warp yarns of the upper and the lower fabric arepositioned between the upper and the lower respectively and the centralweft insertion means, each time a weft yarn (1) is inserted at the backof the respective fabric.
 13. Method according to claim 1, characterizedin that at least two pile warp systems (6, 7, 8, 9, 16, 17, 18, 19) areprovided per reed dent.
 14. Method according to claim 1, characterizedin that the said weaving machine is provided either for disconnecting atleast one weft insertion means and/or for not presenting a weft yarn (1)to at least one weft insertion means.
 15. Method according to claim 1,characterized in that the weft insertion means are provided with adriving device in order to carry the weft insertion means through theshed, and in that the weaving machine is provided for receiving any weftinsertion means in order to select during each cycle (a, b, c, d)whether a weft insertion means will be carried through the shed or notby connecting the respective weft insertion means to or by disconnectingit from its driving device.
 16. Method according to claim 15,characterized in that connecting or disconnecting the weft insertionmeans to or from its driving device may be performed in anelectromotive, electropneumatic or electrohydraulic manner.
 17. Pilefabric, characterized in that said fabric will comprise at least onearea which is manufactured according to a method in accordance withclaim
 2. 18. Weaving machine for weaving a face-to-face pile fabriccomprising binding and tension warp yarns (4, 5, 14, 15), weft yarns (1)and at least 40 pile warp yarns (6, 7, 8, 9, 16, 17, 18, 19) percentimetre which in at least one part of the fabric, alternately in theupper and in the lower fabric, are interlaced, forming a pile around aweft yarn (1) and which in another part of the fabric are interlaced,not forming a pile, in one of the backing fabrics, characterized in thatthe said weaving machine is comprising three weft insertion means and isprovided for inserting only one weft yarn (1) at each weft insertioncycle, the pile warp yarns not forming a pile to be interlaced in theupper fabric and the pile warp yarns not forming a pile to be interlacedin the lower fabric being positioned each on a different level (N1, N2)and, in successive series of four weft insertion cycles (a, b, c, d),each time during two successive weft insertion cycles (a, b), one weftyarn (1) being inserted, under the two levels (N1, N2) and one weft yarn(1) being inserted above the two levels N1, N2) and one weft yarn (1),each time during two other successive weft insertion cycles (c, d) beinginserted in each of these weft insertion cycles between the said levels(N1, N2).
 19. Weaving machine according to claim 18, characterized inthat pile forming pile warp yarns are interlaced only around weft yarnshaving been inserted below or above the two levels (N1, N2) at which nonpile forming pile warp yarns are positioned to be interlaced in theirbacking fabrics.
 20. Weaving machine according to claim 18,characterized in that said weaving machine is a three rapierface-to-face weaving machine provided with an non open shed Jacquardmachine.
 21. Weaving machine according to claim 18, characterized inthat said weaving machine is a three rapier face-to-face weaving machineprovided with an open shed Jacquard machine.